Cannot login and get error when trying to connect to MSCommerce PowerShell

Question

I have a feeling I'm not the first person with this error, yet I cannot seem to find an answer and Microsoft Support have just fobbed me off.

I am trying to check our Self-Service Options for M365 and when trying to login to the MSCommerce powershell module, it prompts for id, password & mfa (as normal), but then gives error:

Use AllowSelfServicePurchase for the MSCommerce PowerShell module

PS> Connect-MSCommerce 

Sorry, but we’re having trouble with signing you in.

**AADSTS50011: The redirect URI 'http://localhost:61075' specified in the request does not match the redirect URIs configured for the application '3d5cffa9-04da-4657-8cab-c7f074657cad'. Make sure the redirect URI sent in the request matches one added to your application in the Azure portal. Navigate to https://aka.ms/redirectUriMismatchError to learn more about how to fix this.
**
Three separate GA's have tried this and we all get the same error. I cannot find an application with that ID in our tenant. What are we missing please?

Thanks in advance.